In July 2003 representatives from Clonmel Evergreen and St Olivers Boys met to consider the possibility of both clubs amalgamating. The meeting was held in a community house in Elm Park and present on behalf of Evergreen were Michael McArdle, Gussy Sweetman and Noel Meaney while John Power, Karl Condon and Richie Kiely represented St Olivers Boys. Also there as facilitators, for want of a better word, were Marion Smiles and Eileen Anderson from RAPID (Revitalising Areas by Planning, Investment and Development). One of the action plans of the Rapid programme is to support organisations expand their sports and recreational facilities and both Marion and Eileen saw the formation of a new club based in the west side of Clonmel as contributing to this. Both girls made themselves available if the amalgamation talks ran into difficulty but both clubs were committed to the new venture and August 2003 saw Clonmel Celtic participate in the Tipperary Southern & District League for the first time. Both St Olivers Boys and Clonmel Evergreen were well established junior teams in Clonmel. In 1998 St Olivers and St Martins merged to form St Olivers Boys. For the past few years the team had been trying to acquire their own playing facilities but to no avail. A very decent junior team did result from the merger and this team grew in strength and began to compete well with the more established clubs in Tipperary like St Michaels and Clonmel Town. Indeed the team did come close to a title in 2002 finishing runners up. Clonmel Evergreen for their part were a strong unit during the nineties and also came close to winning the league but again Town and Michaels seemed to be always there to deny them silverware. However they did purchase their own playing pitch from Clonmel Og on the Clonmel Bypass near the Fethard Rd Roundabout. Unfortunately on the pitch the junior team hit bad times, which saw them relegated from the Premier League for the first time. They did have a very promising youth team. So a well-established junior team, a youth team with a lot of potential and a fine soccer pitch were all factors, which made the amalgamation an attractive option. Clonmel Celtic’s first year in competition was a memorable one with the youths winning the Munster Youths Cup and the club being awarded government grants of up to €200,000 to help develop their own facilities. For the historians among us lets delve into the past and have a look at the history of the teams that now make up Clonmel Celtic FC.

The story of St Olivers Boys seems to be one long story of amalgamations which can be traced all the way back to 1977. In that year Clonmel Rangers combined with Elm Park United to form Elm Park Rangers. The club used the Elm Park community pitch and drew a large volume of players form far and wide. They also built up a large support base in their own immediate area. Founder members of Elm Park Rangers were Danny and Richie Gibbons and Michael Lynch who felt that the northern part of Clonmel was devoid of a soccer team and they also realised the potential in the largely populated residential area. Their ambitions were realised in the first year when they beat old rival Clonmel Hibs in a Shield Final with captain John Smith scoring the winning goal. They won promotion to the 1st Division many times but failed to make the mark. They appeared in several cup and shield finals, but lady luck did not always smile on them. They seemed to be labelled with the tag 'Always the bridesmaids never the bride'. However, their fortune changed in the 1989/90 shield final when they won the 2nd Division Shield final with a victory over Knocklong. A beauty of a free kick won the day for Elm Park Rangers and it was a proud Ned Cullinane who received the 2nd Division Shield from league chairman Gay Lowry. They had a constant reservoir of young players coming through their schoolboy and youth ranks and in the early nineties they changed their name to St Olivers. The nineties were a decade of huge success for the schoolboy and youth teams and the club soon developed a reputation for their under age talent. Unfortunately, although the junior side tasted promotion a few times, they were never serious challengers for the Premier League. The club never seemed able to hold onto to their youths and this had a detrimental effect on the junior team. In 1998 St Olivers joined with St Martins to form St Olivers Boys and more and more youths seemed to stay with the club, which saw St Olivers Boys become a very respected outfit in the Tipperary League.

Clonmel Evergreen FC was established in 1978 and developed into a very successful team in the TS.D.L. The club carved out its own special area in the soccer stronghold of Clonmel. From its beginning it was fortunate to have talented players at its disposal. It won the 3rd division in convincing fashion in the 1979-80 season. It has the proud achievement of gaining promotion to the Premier Division in two successive seasons. They quickly established themselves as a major force in the Premier and were a permanent fixture in this division for over 20 years. The club consolidated their league position but were unfortunate in that major honours eluded them. They were runners up in the First Division in 1987 and 1988 and again in 1997 and 2001. 2001 proved to be a good year for the club as they also won the First Division cup, beating Kilmanahan in the final, 2 goals to nil. Clonmel Evergreen had a reputation as cup specialists. Their two notable successes to date in the Tipperary Cup were against Borris in 1981 and again against Clonmel Rangers in 1982. Jimmy Anderson was the founding father of the club and worked tirelessly to promote and develop it. During the late eighties and early nineties the club placed a tremendous emphasis on developing schoolboy and youth teams. At one stage they had teams playing at every age level from under 10 right up to youths. As mentioned earlier on the playing front the club hit some barren times in recent years and in July 2003 decided that the best way forward for everyone involved in the club was to amalgamate with St Oliver Boys to form Clonmel Celtic Football Club.

St Martins were established in 1984 and soon became a force in the TS&DL. Players were meeting on a regular basis for games in the Loreto Convent and Marlfield. A dedicated committee, led by Eric Martin and Patrick Power, organised a club around these players and gained promotion in successive seasons. The club achieved their first notable success when they won the 3rd Division Shield in 1986. The teams fortunes fluctuated for a while but the club re-organised in the 1991/92 season and won the Division 3 title in convincing manner. In the same season the club came very close to winning the Tipperary Cup, having accounted for a few premier teams in the earlier rounds of the competition. St Martins won promotion to the Premier League in 1993 and made this year the most successful in the club's history by winning the 1993 1St Division Shield by beating Borris in an epic final. In the beginning the club played its matches at Ballyneale Park but then moved to the By Pass Rd, Clonmel. Following promotion the club acquitted itself well in the Premier Division. It was always the club's intentions to develop a youth policy and in 1998, with the club interested in getting involved with schoolboy and youth football, they joined with St Olivers to form St Olivers Boys FC.

Under the expert guidance of managers Kenny O’Shea and Carl Condon Clonmel Celtic grew into a very good soccer team in the late noughties. Although the club’s had tasted success when winning the Munster Youths Cup in 2004 with a 2-0 win against Waterford Bohemians they had never won a trophy at Junior Level. This all changed in May 2009 when Clonmel Celtic brought the Tipperary Cup back to Kate Ryans after a memorable 2-1 win over neighbours Clonmel Town in Cahir. It was the start of a golden period for the club at Junior level and in 2010 they successfully defended the Tipperary Cup after a 3-1 extra time win over Carrick team Rock Rovers. Things were to get even better for the club and they made another major breakthrough in 2013 when for the first time the won the TSDL Premier League. In 2015 they repeated this feat even more impressively by clinching the TSDL Premier League title again with a 1-0 win in their last game away to reigning champions St Michaels. By now Celtic were also beginning to make an impression outside the county with runs to the semi finals of the FAI Junior Cup in 2012 and 2015 and a Munster Junior Cup Final appearance in 2013. In 2013 the won their only provincial trophy to date when they defeated Clare side Avenue Utd 2-1 in the final of the Munster Champions League Trophy Final at Celtic Park.

Clonmel Celtic also caters for Schoolboy and Ladies soccer. Although the club always had schoolboy teams in 2010 they opened their soccer Academy that was in effect an effort to build from the bottom up. The Academy has been great success introducing many new children and coaches to the club. The club was the only club in town to cater for female participation in soccer and currently have a team participating in the Tipperary Ladies Soccer Summer League.

The club’s purple patch on the pitch over the last decade has also been matched by developments off the pitch. During this period the club, with the assistance of Sport Capital Grants, built dressing rooms, an All Weather pitch and happy produced one of the finest natural playing surfaces in the regions that in April 2015 played host to an U15 Schoolboys International between Republic of Ireland and the Czech Republic. The club's latest capital development was a 150 seater Stand that was officially opened by CEO John Delaney when he visited the club during the FAI Festival of Football in July 2015.

On the subject of internationals former player Luke Kiely was capped with the Republic of Ireland U15s while club captain David Joyce is currently (May 2017) involved with the Republic of Ireland amateur team preparing for the UEFA Regions Finals to be played in Turkey in July 2017.